U.S. Pat. No. 4,105,776 discloses proline derivatives and related compounds having the formula ##STR2## wherein R is hydroxy, NH.sub.2 or lower alkoxy;
R.sub.1 and R.sub.4 each is hydrogen, lower alkyl, phenyl or phenyl-lower alkyl; PA1 R.sub.2 is hydrogen, lower alkyl, phenyl, substituted phenyl wherein the phenyl substituent is halo, lower alkyl or lower alkoxy, phenyl-lower alkyl, diphenyl-lower alkyl, triphenyl-lower alkyl, lower alkylthiomethyl, phenyl-lower alkylthiomethyl, lower alkanoyl-amidomethyl, ##STR3## R.sub.3 is hydrogen, hydroxy or lower alkyl; R.sub.5 is lower alkyl, phenyl or phenyl-lower alkyl; PA1 R.sub.6 is lower alkyl, phenyl, substituted phenyl (wherein the phenyl substituent is halo, lower alkyl or lower alkoxy), hydroxy-lower alkyl or amino(carboxy)lower alkyl; ##STR4## M is O or S; m is 1 to 3; PA1 n and p each is 0 to 2,
and to processes for making them.
The asterisks indicate asymmetric carbon atoms. Each of the carbons bearing a substituent R.sub.1, R.sub.3 and R.sub.4 is asymmetric when that substituent is other than hydrogen.
The above compounds are useful as inhibitors of the conversion of the decapeptide angiotensin I to angiotensin II and thus are useful in reducing or relieving angiotensin related hypertension.
U.S. Pat. No. 4,112,096 discloses 2-(hydroxymethyl)pyrazolo[1,5-c]quinazolin-5-one which has the structure ##STR5## This compound is useful in treating allergic conditions.